Surface modification of polyester by oxygen‐ and nitrogen‐plasma treatment

Abstract

In this paper, we present a study on the surface modification of polyethyleneterephthalate (PET) polymer by plasma treatment. The samples were treated by nitrogen and oxygen plasma for different time periods between 3 and 90 s. The plasma was created by a radio frequency (RF) generator. The gas pressure was fixed at 75 Pa and the discharge power was set to 200 W. The samples were treated in the glow region, where the electrons temperature was about 4 eV, the positive ions density was about 2 × 10 15 m −3 , and the neutral atom density was about 4 × 10 21 m −3 for oxygen and 1 × 10 21 m −3 for nitrogen. The changes in surface morphology were observed by using atomic force microscopy (AFM). Surface wettability was determined by water contact angle measurements while the chemical composition of the surface was analyzed using XPS. The stability of functional groups on the polymer surface treated with plasma was monitored by XPS and wettability measurements in different time intervals. The oxygen-plasma-treated samples showed much more pronounced changes in the surface topography compared to those treated by nitrogen plasma. The contact angle of a water drop decreased from 75• for the untreated sample to 20• for oxygen and 25• for nitrogen-plasma-treated samples for 3 s. It kept decreasing with treatment time for both plasmas and reached about 10• for nitrogen plasma after 1 min of plasma treatment. For oxygen plasma, however, the contact angle kept decreasing even after a minute of plasma treatment and eventually fell below a few degrees. We found that the water contact angle increased linearly with the O/C ratio or N/C ratio in the case of oxygen or nitrogen plasma, respectively. Ageing effects of the plasma-treated surface were more pronounced in the first 3 days; however, the surface hydrophilicity was rather stable later.

Plasma Induced Hydrophilic Cellulose Wound Dressing

“…Many authors agree that probability for surface de-excitation of molecules with the excitation energy of only 1 eV is always low and practically independent from characteristics of solid materials. On the other hand, the literature on interaction between neutral oxygen atoms and solid materials abounds [76][77][78][79][80].…”

“…This observation is sound with effects reported in appropriate literature. Namely, many authors have shown that a treatment of organic materials with gaseous plasma leads to increased surface roughness [77,[81][82][83]. While the effect is not yet fully understood, a plausible explanation is selective interaction with amorphous and crystalline segments of cellulose materials.…”

An in vitro bacterial adhesion assessment of surface-modified medical-grade PVC

“…This new morphology is advantageous for following coupling processes due to an increased surface area and roughness [5]. In fact, the generated pattern on the sample 2 surface is a consequence of competition between functionalization and ablation phenomena both leading to surface restructuring [8]. The occurrence of ablation is ascertained via gravimetric means where a weight loss of ^4fjugcm -2 has been observed due to the plasma treatment for 15 s implying an etching rate of ~2 nm/s taking into account the density of the PVC grade used.…”

“…This multistep approach has aroused great interest thanks to several advantages such as convenient and controllable introduction of biocidal species with a high surface density together with precise localization and long stability of the grafted layers [6,7]. In the first phase, a preliminary functionalization has to be achieved regarding an inherent lack of active entities on the pristine substrate, where low temperature-atmospheric pressure plasma treatment has been proved to be effective therein [8,9]. However, the necessity to shorten the treatment duration to a few seconds calling for rather high plasma power density remains a critical impediment to largescale applications of this type of plasma [10].…”

The allylamine grafting on the plasma pre-treated polyester nonwoven fabric: Preparation, characterization and utilization

“…The plasma treatment modifications of the PET surfaces are frequent in order to improving wettability [10] or water-repellent improvement [11]. Consequently, the treatment goals are very often functional water compatible group binding, such as -COOH, -OH, -NH2 [7][8][9][12][13][14][15][16][17][18][19][20][21], or Ti02/ Mo03 [22]. Moreover, the amine (-NH2) groups are very important for chemical reactions with proteins or surface interactions with cells [1].…”